[html] Best HTML5 markup for sidebar

The book HTML5 Guidelines for Web Developers: Structure and Semantics for Documents suggested this way (option 1):

<aside id="sidebar">
    <section id="widget_1"></section>
    <section id="widget_2"></section>
    <section id="widget_3"></section>
</aside>

It also points out that you can use sections in the footer. So section can be used outside of the actual page content.